Kevin Costner and Francis Ford Coppola’s idiots certainly made a splash – with the worst ever.

If you film it, they will come, Kevin said.

I’ll make them an image they can’t refuse, Francis said.

And respectively, they didn’t do this and they did that.

While the summer box office has been buoyed by hits like “Inside Out 2” and “Deadpool & Wolverine,” two very expensive projects from big-name directors have stumbled embarrassingly, drawing groans and snubs on several continents: Kevin Costner’s “Horizon: An American Odyssey” and Francis Ford Coppola’s “Megalopolis.”

What were these idiots thinking? Beloved artists willingly allowed themselves to become mere lines for ridicule of their expensive projects.

Both films cost the famous directors upwards of $100 million of their own money, and they certainly caused a stir—in the worst possible way.

This week, the 85-year-old Coppola released a new trailer for his $120 million epic “Megalopolis,” which tells the story of the turbulent rebirth of a city that critics politely scorned when it premiered at Cannes.

The clip includes quotes from reviews of his previous works by the likes of Pauline Kael and John Simon to prove that Coppola’s films, like his wine, get better with age.

The problem is that all the quotes were made up or ripped from parts of other movies. You’d be shocked to learn that most people loved The Godfather when it came out.

It’s the latest insult to “Megalopolis,” which Coppola has been toying with since 1977 and sold part of his wine business to finance.

After a rocky start in France, this massive indie hit had trouble finding distribution.

The film’s last chance for a second act is its North American premiere at the Toronto International Film Festival in two weeks. I’ll be there, pen in hand!

Costner’s Horizon, another waste of time, has already been released in theaters, but it has been a miserable failure.

The Field of Dreams actor, who directed the infamous Waterworld, apparently learned nothing from this early embarrassment.

The 68-year-old left Yellowstone National Park and mortgaged his California property to finance his $98 million project.

He conceived Horizon — which he wrote, directed and starred in — as an extended, four-part Western, a Game of Thrones-style movie with vehicles and dozens of interconnected characters.

Oh, that “first chapter” was so painful, the thoughts were running through my mind.

The utterly boring film was screened at Cannes to derision and ridicule. When it was shown in local cinemas, I gave it one star, saying, “I can’t imagine devoting another 540 minutes of my time to this bloated journey.”

But Costner has a firm belief in his vision, however vague it may be.

“I did it without thinking.” He told Deadline,“This gave my accountant a huge tantrum. But this is my life, and I believe in the idea and the story.”

But audiences weren’t happy about it. “Chapter One” grossed only $34 million, and as a result the August release date for the sequel was canceled.

His last hope is that the Venice premiere of “Chapter II” on September 7 will garner more attention than the first screening.

Of course, you have to admire a little that these guys are doing their best in the relentless pursuit of originality. And that’s a good thing for them.

But, no matter what Coppola’s bogus trailer claims, history will look back on these “passion projects” as foolish acts of hubris. Nothing more.

Costner and Coppola, the saddest duo this year.